Spring-loaded tilting brackets for implement cabs

ABSTRACT

An operator cab swingable between a normal, lowered position and a raised, tilted position has a double-acting compression spring associated with each hinge of the cab which transmits sufficient lifting force to the cab to enable one man to swing the heavy cab between such positions and also functions to cushion the descent of the cab as the center of gravity thereof shifts from one side to the opposite side of its axis.

United States Patent [1 1 Voth [451 Aug. 14, 1973 SPRING-LOADED TILTING BRACKETS FOR IMPLEMENT CABS [75] lnventor:

[7 3] Assignee: Full Vision, Inc., Newton, Kans.

[22] Filed: Oct. 26, 1971 [21] App]. No.: 192,494

Charley Voth, Hesston, Kans.

[52] US. Cl 296/35 R, 16/190, 180/89 A [51] Int. Cl. 362d 33/06 [58] Field of Search 180/89 A; 296/28 C,

[56] References Cited UNITED STATES PATENTS 2,951,548 9/1960 Crockett et a1 180/89 A 3,039,557 6/1962 Boyce et a] 180/89 A 3,352,598 11/1967 Anderson 296/35 R 3,354,499 11/1967 Anderson.... 16/180 3,457,584 7/1969 Phelps 16/190 3,561,162 2/1971 Goldman 49/379 X 1,043,827 11/1912 Hart1ey..... 267/171 X 3,425,386 2/1969 Campbell 16/180 X FOREIGN PATENTS OR APPLICATIONS 811,652 8/1951 Gennany 16/190 Primary Examiner-Leo Friaglia Assistant Examiner-Leslie .1. Papemer Attorney-Schmidt, Johnson, l-lovey & Williams [5 7] ABSTRACT An operator cab swingable between a normal, lowered position and a raised, tilted position has a double-acting compression spring associated with each hinge of the cab which transmits sufficient lifting forceto the cab to enable one man to swing the heavy cab between such positions and also functions to cushion the descent of the cab as the center of gravity thereof shifts from one side to the opposite side of its axis.

6 Claims, 9 Drawing Figures SPRING-LOADED TILTING BRACKETS FOR IMPLEMENT CABS This invention relates to tiltable operator cabs for power equipment such as farm tractors, earth moving machines, and industrial apparatus of various types and has as an important object thereof the goal of providing efficient, noncomplex, double-acting assisting structure for each hinge of the cab which enables one man to raise the heavy cab to a tilted position without the aid of others by virtue of the fact that the double'acting structure supplies lifting force in one direction to the cab at one end of its path of travel and cushioning force in the opposite direction at the opposite end of its path of travel.

Another important object of the present invention is the provision of double-acting structure as aforesaid which is equally effective in the reverse situation to enable one man to return the tilted cab to its initial position by himself as the lifting and cushioning functions of the structure are reversed.

A further important object of the present invention is to provide a variable lost motion assembly in conjunction with such structure which permits the amount of swinging of the cab during which the latter is unaided by the structure to be varied to the extent desired.

In the drawings: 7

FIG. I is a schematic elevational view of a farm tractor representing one form of power equipment which utilizes a tiltable operator cab unit constructed in accordance with the principles of the present invention, various tilted positions of the cab being illustrated in phantom;

FIG. 2 is an enlarged, fragmentary, perspective view of the rear axle area of the tractor in FIG. 1 showing details of construction of the cab unit;

FIG. 3 is an enlarged, fragmentary, side elevational view of the unit with the cab in its normal, lowered position, parts being broken away and shown in cross section for clarity;

FIG. 4 is a fragmentary, rear elevational view of the unit in FIG. 3',

FIG. 5 is an enlarged, fragmentary, side elevational view of the unit similar to FIG. 3 but showing two additional positions of the cab;

FIG. 6 is an enlarged, fragmentary, cross-sectional view of the unit taken along line 6-6 of FIG. 4 and showing the position of the cab after release of the hold-down means for the cab; I

FIG. 7 is a fragmentary, cross-sectional view of the unit taken along line 7-7 of FIG. 3;

FIG. 8 is an enlarged plan view of the components of the lost motion assembly of the unit; and

FIG. 9 is an elevational view of the components of FIG. 8.

The tractor 10 has a frame including a rear wheel axle housing 12 (FIGS. 1 and 2) which supports the cab unit of presentinvention denoted generally by the numeral 14 between tractor wheels 16. Unit 14 includes a pair of clamps 18, each of which is mounted on housing 12 adjacent a respective wheel 16 and has a pair of opposed plates which conform to the particular configuration of housing 12. In this respect, it is to be understood that plates 20 of each clamp 18 may assume any number of various configurations, depending upon the configuration of the axle or other frame member of the equipment upon which the cab unit 14 is to be installed.

The top plate 20 of each clamp 18 has a pair of upright, rearwardly inclined and laterally spaced support arms 22 welded to plate 20 which carry a transverse hinge bolt 24 (FIGS. 3-7) extending therebetween at the upper ends thereof. A pair of plates 26 are welded to each set of the arms 22, respectively, along the upper rear margins thereof and project downwardly away from arms 22 to support an elongated, open-ended box 28 secured thereto by fasteners 30. The box 28 contains yieldable biasing means in the nature of a single, elongated, coiled compression spring element 32 (FIGS. 3, 5 and 6) having a pair of caps 34 at opposite ends thereof disposed in alignment with respective end openings 36 of the box 28. As shown in FIG. 4, the box 28 and its openings 36 are disposed midway between the two arms 22.

The two sets of arms 22 cooperate to hingedly support a hollow operator cab 38 for swinging movement of the latter between a normal, lowered solid line position of FIG. 1, and a raised, tilted position illustrated in phantom in FIG. 1. Cab 38 includes a pair of rigid, up wardly extending, tubular braces 40 on opposite sides thereof which lend structural rigidity to cab 38 and are each pivotally mounted at the lowermost ends thereof on a respective hinge bolt 24 between arms 22. A handle 42 is affixed to the front of cab 38 for facilitating swinging of the latter about a horizontal axis extending through bolts 24, and a pair of step assemblies 44 are mounted on the frame of tractor 10 on opposite sides of the latter, each step assembly 44 having releasable fastening means 46 in the nature of a bolt and nut which interconnect the cab 38 and assembly 44.

A lost motion assembly 48, shown in detail in FIGS. 8 and 9, is pivotally supported by each set of arms 22 for free-swinging movement relative to arms 22 and cab 38 about hinge bolt 24, and each assembly 48 includes a bifurcated member 50 constructed from a pair of juxtaposed plates formed to present the Y-shaped configuration of FIG. 9. Each member 50 at the upper end thereof receives the corresponding brace 40, has a pair of opposed, outstanding hubs 52 (FIGS. 7-9) which project into corresponding arms 22 to receive the bolt 24, and is provided with a pair of spaced-apart abutments in the nature of a pair of legs 54 which define a mouth 56 therebetween. As shown best in FIG. 6, the mouth 56 partially receives box 28, and legs 54 are disposed in alignment with corresponding box openings 36 for engagement with a proximal cap 34. A pair of adjustable limit devices 58 project outwardly from opposite sides of each member 50 for limiting swinging of the latter relative to cab 38, each device 58 including a short supporting bar 60 welded to member 50 and projecting outwardly at an angle therefrom which carries a setscrew 62 engageable with a corresponding proximal portion of the brace 40.

During normal operation of tractor 10 the cab 38 is disposed in its normal, lowered position illustrated in FIG. 1 with the retaining fasteners 46 securely holding cab 38 in position. As shown in FIG. 3, the lost motion assemblies 48 are disposed at one end of their respective arcuate paths of travel as the lower limit devices 58 are engaged by the bottoms of braces 40 to transmit a counterclockwise compressive force to springs 32 through the lower legs 54 of members 50. Upon release of the fasteners 46, each spring 32 urges the corresponding assembly 48, and hence cab 38, in a clockwise direction with sufficient strength to enable the operator of tractor I to grasp handle 42 and raise the cab 38 to the tilted position thereof as shown by the solid lines in FIG. 5 and by the phantom lines in FIG. 1 without additional assistance from other persons. As shown by solid lines in FIG. 6 and by phantom lines in FIGS. 1 and 5, the coil springs 32 are capable of holding the cab 38 in an intermediate position within which the cab 38 is tilted a sufficient extent to allow access to certain of the components of tractor 10 without the need for completely raising cab 38.

Once the cab 38 is raised beyond the intermediate position thereof, the springs 32 are no longer compressed by the lower legs 54 of members 50 and hence offer no assistance to raising of the cab 38 beyond this point. However, it will be appreciated that as the center of gravity of cab 38, which was initially disposed on the left side of the pivotal axis thereof defined by hinge bolts 24, approaches the vertical plane of such axis, the cab 38 becomes progressively easier to swing rearwardly and thus the additional help of springs 32 is not required at this time. Without the biasing action of springs 32 against lower legs 54, the members 50 remain in a substantially stationary condition as the braces 40 leave the lower limit devices 58 and travel in a clockwise direction toward the upper limit devices 58. Once the center of gravity of cab 38 passes to the opposite side of bolts 24, the upper devices 58 are engaged by braces 40 and the cab 38 gains momentum as it moves toward its completely tilted position. Assemblies 48 are thus rotated in a clockwise direction to bring the upper legs 54 thereof through the upper openings 36 in boxes 28 to compress springs 32 in a clockwise direction as shown in FIG. 5. Thus, instead of slamming against a rigid stop or the like, after gaining substantial momentum, the cab 38 is progressively cushioned to virtually eliminate any possibility of damage thereto.

While the cab 38 is in its fully tilted position, it may be seen that access is easily gained to the area previously protected by cab 38 for servicing components within such area and, once servicing has been completed, the cab 38 may be easily returned to its original position by simply swinging the same in a counterclockwise direction. It will be appreciated that, once again, the springs 32 assist in swinging of the cab 38 as they seek to return to an uncompressed condition in a counterclockwise direction. Further, once the center of gravity of cab 38 has been shifted past bolts 24 onto its original side of the latter, the cab 38 gains momentum but is cushioned against a damaging, abrupt collision with the tractor frame by virtue of the fact that springs 32 become progressively compressed by lower legs 54 of assemblies 48. Once the cab 38 has reached its intermediate position it may be pulled downwardly into its fully lowered, normal position by handle 42, whereupon the fasteners 46 may be replaced on both sides of tractor I0 to place cab 38 in condition for reuse.

It should be noted that the extent of lost motion afforded by the assemblies 48 may be varied considerably by adjustment of the setserews 62. In this manner, the distance through which cab 38 swings without the aid of springs 32 may be varied to obtain the desired amount of assistance from springs 32.

Through the use of double-acting compression springs 32 and lost motion assemblies 48, it is apparent that the concept of providing a tilting cab on a tractor or other power equipment has been substantially advanced in a practical sense. Heretofore it has been virtually impossible for one person to raise the heavy cab,

sometimes weighing in the neighborhood of 900 pounds, to a tilted position, although manifestly, such tiltability of the cab was extremely desirable. When the tractor required service in an unaccessible area covered by the cab it was impossible to raise the latter without the combined efforts of several men. Now, however, the cab may be raised at any time by one man whether such is necessary in the field when the operator may be isolated from others, or in the shop where additional help may be more easily obtained. Moreover, the possibility of damage to the cab during tilting thereof is virtually eliminated. And all of this is made possible through the unique, double-acting functions of springs 32 which are closely associated with the hinges for the cab defined by arms 22 and bolts 24. Without such an arrangement, it is likely that expensive and complex hydraulic mechanism would need to be employed in order to provide a cab having the high degree of practical tiltability available with the presentinvention.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A tiltable operator cab unit for equipment having a load-bearing frame, said unit comprising:

an operator cab;

means pivotally mounting said cab on said frame for swinging movement of the cab between a normal, lowered position wherein the center of gravity of the cab is disposed on one side of the pivotal axis of the cab and a tilted position wherein the center of gravity of the cab is disposed on the opposite side of said axis;

a double-acting biasing element on said frame operable to aid in manual swinging of the cab from the normal to the tilted position thereof and to effect cushioning of the cab when the center of gravity thereof passes from said one side to the opposite side of said axis; and

a lost motion assembly coupling said element with the cab to discontinue the assistance by said element for an intermediate distance as the cab is swung between said positions.

2. The unit'as claimed in claim I, wherein said element comprises a coiled compression spring responsive to swinging of the cab between said alternate positions thereof to compress in alternate, opposite directions corresponding to the direction of swinging of the cab.

3. The unit as claimed in claim 1, wherein said assem bly includes a member pivotally supported for swinging movement relative to said frame and to the cab, said member being provided with limit means engageable with said cab for determining the extent of free swinging of the member relative to the cab and having a pair of spaced apart abutments disposed on opposite sides of said element and alternately engageable with the latter.

4. The unit as claimed in claim 3, wherein said pivotal axis of the cab and the pivotal axis of said member coincide.

5. The unit as claimed in claim 3, wherein said limit means includes a pair of adjustable devices on opposite sides of said member for varying the amount of lost motion.

6. The unit as claimed in claim 3, wherein said element comprises a coil compression spring, and wherein is provided a box rigidly affixed to said frame and containing said spring, said box having a pair of opposed, open ends clearing said abutments for compression of said spring from either of said alternate directions.

t t i l il 

1. A tiltable operator cab unit for equipment having a loadbearing frame, said unit comprising: an operator cab; means pivotally mounting said cab on said frame for swinging movement of the cab between a normal, lowered position wherein the center of gravity of the cab is disposed on one side of the pivotal axis of the cab and a tilted position wherein the center of gravity of the cab is disposed on the opposite side of said axis; a double-acting biasing element on said frame operable to aid in manual swinging of the cab from the normal to the tilted position thereof and to effect cushioning of the cab when the center of gravity thereof passes from said one side to the opposite side of said axis; and a lost motion assembly coupling said element with the cab to discontinue the assistance by said element for an intermediate distance as the cab is swung between said positions.
 2. The unit as claimed in claim 1, wherein said element comprises a coiled compression spring responsive to swinging of the cab between said alternate positions thereof to compress in alternate, opposite directions corresponding to the direction of swinging of the cab.
 3. The unit as claimed in claim 1, wherein said assembly includes a member pivotally supported for swinging movement relative to said frame and to the cab, said member being provided with limit means engageable with said cab for determining the extent of free swinging of the member relative to the cab and having a pair of spaced apart abutments disposed on opposite sides of said element and alternately engageable with the latter.
 4. The unit as claimed in claim 3, wherein said pivotal axis of the cab and the pivotal axis of said member coincide.
 5. The unit as claimed in claim 3, wherein said limit means includes a pair of adjustable devices on opposite sides of said member for varying the amount of lost motion.
 6. The unit as claimed in claim 3, wherein said element comprises a coil compression spring, and wherein is provided a box rigidly affixed to said frame and containing said spring, said box having a pair of opposed, open ends clearing said abutments for compression of said spring from either of said alternate directions. 